Sweat the onions in oil, add the carrots cut into slices and the potato cubes, season with garlic, pepper and the stock without water, and let the lid sweat briefly.
Pour 1 liter of water or stock and gently cook, covered, until the carrots and potatoes are soft. Add 1 cup of cream and puree everything. If the soup is too creamy, add a little more stock until the consistency is right.